Convection in Fluids
📋 What it is
In convection, heated fluid rises and cool fluid sinks, setting up a circulating current that carries heat.
🗣️ Coach says
Convection moves heat by moving the STUFF. Heat a fluid (liquid or gas) and it expands, gets less dense, and rises; cooler fluid sinks to take its place. This loop — a convection current — is why hot air rises, why boiling water churns, and why radiators warm a whole room.
🧠 Memory hook
Heat → fluid rises · cool fluid sinks → a circulating convection current carries heat.
😂 Giggle
Why was the insulation so popular?
It always kept things cool under pressure — or warm, depending on the situation!
😲 Whoa!
A hot-air balloon flies on pure convection — heat the air inside so it’s lighter than the cool air outside, and the whole balloon rises.
✅ Quick check: Why does hot air rise?
Say your answer out loud first — then reveal.
Heating makes air expand and become less dense, so it floats up while cooler, denser air sinks.
Convection lifts warm, low-density fluid and drops cool, dense fluid.
🧪 Try it! (2 minutes)
Watch steam or smoke curl upward — you’re seeing a convection current lift warm, light air.